Question

What is the rate of change of flux through a circle with radius r1 inside the solenoid, normal to the axis of the solenoid, and with center on the solenoid axis? Express your answer in terms of the variables R, B, r1, and appropriate constants.

Answer 1

Answer:

$\frac{d\phi}{dt}=\pi r^2\frac{dB}{dt}$

Explanation:

the rate of the magnetic flux is given by,

$\frac{d\phi}{dt}= \frac{d(BA)}{dt}$

where B= magnetic strength

A= area of cross section

r= radius of circle

\phi= flux

=$A\frac{dB}{dt}$

=$\pi r^2\frac{dB}{dt}$